1. Field of the Invention
The present invention relates to an ejector, that is a kinetic pump for transferring a fluid by entrainment with a working fluid discharged at high speed, and that is effectively applied to a refrigerator (hereinafter an “ejector cycle”) in which the ejector is adopted as pump means to circulate a refrigerant.
2. Description of the Related Art
A nozzle of an ejector accelerates a working fluid by decompressing the working fluid. Accordingly, the shape of the inner wall of the nozzle that is in contact with the working fluid requires a high accuracy in machining, i.e., a high accuracy in dimension and a predetermined surface roughness.
In the ejector for an ejector cycle, a speed energy is converted to a pressure energy during mixing of a refrigerant injected from the nozzle and a refrigerant sucked from an evaporator in a pressure increasing portion. Accordingly, similar to the shape of the inner wall of the nozzle, the shape of the inner wall of the pressure increasing portion requires a high accuracy in machining.
Therefore, conventionally, the nozzle is manufactured by electrical discharge machining or wire cut electric spark machining and the pressure increasing portion is manufactured by cutting. However, in the electrical discharge machining, the wire cut electric spark machining and the cutting, it is difficult to reduce the number of man-hours, i.e., the time of machining and, therefore, it is difficult to reduce the cost of manufacturing of the ejector.